This proposal outlines an experimental examination of the role of the substantia nigra pars reticulata (SNr) in the planning and initiation of saccadic eye movements. The SNr has been implicated as an input to the collicular-pontine saccadic control system, but the precise nature of the saccade-related signals in the SNr and their role in the regulation and/or generation of saccade-related signals in the superior colliculus has not been fully investigated. The proposed research will use extracellular electrophysiological recording from the SNr of awake- behaving monkeys to determine which aspects of the movement process are correlated with signals carried by single SNr units and whether those signals have appropriate characteristics to serve as direct precursors to collicular units carrying saccade-related signals.